There are a lot of options that can be configuredfrom the viewer side.

Quick options

The quick options relate to the following configurationsettings:

Auto

LAN

Medium

Modem

Slow

Ultra

View OnlyNo keyboard or mouse events are sent from the viewer to theserver. The server screen can only be viewed, but notcontrolled.Auto scalingThe viewer window is automatically scaled to fit the size ofyour local screen.Use DSM PluginChoose a DSM (Data Stream Modification) Plugin and configureit.To use an encryption plugin, for instance, check this option andselect the plugin in the combo box. The plugin file must be inthe same directory than the vncviewer.exe program. And of course,the same plugin mustbe used by the UltraVNC server you connectto.Proxy/RepeaterSpecify the repeateraddress here.Save connection settings as defaultIf checked, the current settings are saved as default optionsin a configuration file. So next time you run the viewer, youdon't have to reselect all your favorite settings.Further viewer configuration can be done when pressing theOptions button.

[0] number of time the reconnect is attempted 0 (default), never reconnect9 (maximum) 9 time trying reconnect.gui reconnectnumber only for now.This is the number of times a reconnect is made before the viewer close the connection.

Encodings

The server supplies information in whatever format is desiredby the client, in order to make the client as easy as possible toimplement. If the client represents itself as able to usemultiple formats, the server will choose one.

Pixel format refers to the representation of anindividual pixel. The most common formats are 24 and 16 bit"true-color" values, and 8-bit "color map" representations, wherean arbitrary map converts the color number to RGB values.

Encoding refers to how a rectangle of pixels are sent(all pixel information in VNC is sent as rectangles). Allrectangles come with a header giving the location and size of therectangle and an encoding type used by the data which follows.These types are listed below.

Raw

The raw encoding simply sends width*height pixel values. Allclients are required to support this encoding type. Raw is alsothe fastest when the server and viewer are on the same machine,as the connection speed is essentially infinite and raw encodingminimizes processing time.

CopyRect

The Copy Rectangle encoding is efficient when something isbeing moved; the only data sent is the location of a rectanglefrom which data should be copied to the current location.Copyrect could also be used to efficiently transmit a repeatedpattern.

RRE

The Rise-and-Run-length-Encoding is basically a 2D version ofrun-length encoding (RLE). In this encoding, a sequence ofidentical pixels are compressed to a single value and repeatcount. In VNC, this is implemented with a background color, andthen specifications of an arbitrary number of sub rectangles andcolor for each. This is an efficient encoding for large blocks ofconstant color.

CoRRE

This is a minor variation on RRE, using a maximum of 255x255pixel rectangles. This allows for single-byte values to be used,reducing packet size. This is in general more efficient, becausethe savings from sending 1-byte values generally outweighs thelosses from the (relatively rare) cases where very large regionsare painted the same color.

Hextile

Here, rectangles are split up in to 16x16 tiles, which aresent in a predetermined order. The data within the tiles is senteither raw or as a variant on RRE. Hextile encoding is usuallythe best choice for using in high-speed network environments(e.g. Ethernet local-area networks).

Zlib

Zlib is a very simple encoding that uses zlib library tocompress raw pixel data. This encoding achieves good compression,but consumes a lot of CPU time. Support for this encoding isprovided for compatibility with VNC servers that might notunderstand Tight encoding which is more efficient than Zlib innearly all real-life situations.

Tight

Like Zlib encoding, Tight encoding uses zlib library tocompress the pixel data, but it pre-processes data to maximizecompression ratios, and to minimize CPU usage on compression.Also, JPEG compression may be used to encode color-rich screenareas (see the description of -quality and -nojpeg optionsabove). Tight encoding is usually the best choice forlow-bandwidth network environments (e.g. slow modemconnections).

Ultra

Experimental, Ultra encoding provides real time performanceover a LAN by utilizing LZO compression. LZO is a datacompression scheme which is suitable for data de-/compression inreal-time. This means it favors speed over compressionratio.

VNCViewer Toolbar

Send CTRL+ALT+DEL

Toggle Full Screen Mode

Show Connection Options...

Refresh Screen

Send 'Start' (CTRL+ESC) to host

Send Custom Key

Show Status Window

Close Connection

Hide Toolbar Buttons

Toggle Remote Input and Remote Blank Monitor

Open File Transfer...

Select Single Window

Select Full Desktop

Open Chat...

VNCViewer Context Menu

File Transfer... (Hotkey CTRL+ALT+F7)

Open the file transfer dialog window.

Chat... (Hotkey CTRL+ALT+F8)

Open the chat dialog window.

Show/Hide Toolbar (Hotkey CTRL+ALT+F9)

Show or hide the VNCViewer toolbar.

Disable/Enable Remote Input and Monitor

Disable keyboard and mouse input as well as the monitor onthe remote computer.

Connection options... (Hotkey CTRL+ALT+F6)

Open the connection option dialog window.

Connection info

Open the connection info window.

Request screen refresh

Redraw the screen in VNCViewer. Sometimes the display inVNCViewer misses updates or becomes corrupted. A screen refreshcan then insure that VNCViewer's display and remote computer'sdisplay are in sync.

View only

Disables sending mouse and keyboard events from the VNCViewerto the remote computer.

-autoacceptincomingAuto Accept Incoming connection (no SC server info)-autoacceptnodsmserver connection set without encryption, there no message is NOT encrypted while vncviewer listen with dsmplugin-autoreconnect [DelayInSeconds]-autoreconnect (default value 3 seconds)example: autoreconnect after 15 secondsvncviewer.exe -autoreconnect 15 -connect hostnamecommandline autoreconnect default=3 value is number of seconds between reconnects This allow to set a bigger timeout between reconnect intervals this function is blocked by repeater for viewer."%programfiles%\ultravnc\vncviewer.exe" -autoreconnect 30 -connect hostname::5900 -quickoption 3 -dsmplugin SecureVNCPlugin.dsm-reconnect x (warning) not yet available by command line) only guiThis is the number of times a reconnect is made before the viewer close the connection.-disablesponsorremove the sponsor of vncviewer message error-fttimeout sec Filetransfer timeout sec [1-60] -keepalive sec Interval to send a keepalive message -askexitOpen a dialogbox on exit " do you realy want to quit" -restrictedremove options from system menu ( Filetransfer, chat ....) -viewonly Do not send local keyboard or mouse events to the remote computer. -nostatus Don't show the status window while connecting. -nohotkeys Do not enable hot keys (like CTRL+ALT+F9 for full screen mode etc.). Can be useful in case of conflict with other installed software hotkeys. -notoolbar Do not display the toolbar. -autoscalingAutomatically scale the viewer window so that the remote screen fits at best your local screen size. -fullscreen Display viewer in full screen mode. -noautoDisable auto mode. Required for using the color options below or saving a custom configuration (otherwise the settings from quick options always override). -8bit, -256colors, -64colors, -8colors, -8greycolors, -4greycolors, -2greycolors Set the color depth. Fewer colors can significantly reduce the required bandwidth. Note: Grey colors only work with 32 bits color screen resolution. 16 or 24 bits color resolutions just don't work with grey colors. -shared Share the server with other viewers, i.e. allow several viewers to connect simultaneously to the server. -swapmouse Swap left and right button of the mouse. -nocursor Do not display any local dot mouse cursor. -dotcursor Display the local dot mouse cursor. -normalcursor Display the normal local mouse cursor. -belldeiconify not used -emulate3 Emulate a 3-button mouse. -noemulate3 Do not emulate a 3-button mouse. -nocursorshape don't change cursor chapes -noremotecursor "." is used as remote cursor -scale A/B Scale the display by the factor A/B. -emulate3timeout Timeout emulate 3 button mouse with 2 buttons -emulate3fuzz Emul3Fuzz emulate 3 button mouse with 2 buttons -disableclipboard Do not transfer clipboard content. -delay delay debug option -loglevel loglevel Set the loglevel. This can range from 0 (minimal) to 10 (maximum logging). -consoleOpen a console window for log output. -logfile filename Log to the file specified by filename. -config filename Read the configuration from filename. -register Record the path to the VNC viewer and the type of the .vnc files in the registry -encoding encoding Encoding is either raw, rre, corre, hextile, zlib, zlibhex, tight or ultra. Encodings are described here. -compresslevel level Use specified compression level (0..9) for "tight" and "zlib" encodings (Tight encoding specific). Level 1 uses minimum of CPU time and achieves weak compression ratios, while level 9 offers best compression but is slow in terms of CPU time consumption on the server side. Use high levels with very slow network connections, and low levels when working over high-speed LANs. It's not recommended to use compression level 0, reasonable choices start from the level 1. -quality qualityUse the specified JPEG quality (0..9) for the "tight" encoding (Tight encoding specific). Quality level 0 denotes bad image quality but very impressive compression ratios, while level 9 offers very good image quality at lower compression ratios. Note that the "tight" encoder uses JPEG to encode only those screen areas that look suitable for lossy compression, so quality level 0 does not always mean unacceptable image quality. -user msuserms logon (NTLM1) username set at server (not viewer side)